The mass limit of white dwarfs with strong magnetic fields in general relativity

Recently, U. Das and B. Mukhopadhyay proposed that the Chandrasekhar limit of a white dwarf could reach a new high level （2.58M） if a superstrong magnetic field were considered （Das U and Mukhopadhyay B 2013 Phys. Rev. Lett. 110 071102）, where the structure of the strongly magnetized white dwarf （SMWD） is calculated in the framework of Newtonian theory （NT）. As the SMWD has a far smaller size, in contrast with the usual expectation, we found that there is an obvious general relativistic effect （GRE） in the SMWD. For example, for the SMWD with a one Landau level system, the super-Chandrasekhar mass limit in general relativity （GR） is approximately 16.5% lower than that in NT. More interestingly, the maximal mass of the white dwarf will be first increased when the magnetic field strength keeps on increasing and reaches the maximal value M = 2.48MQ with BD = 391.5. Then if we further increase the magnetic fields, surprisingly, the maximal mass of the white dwarf will decrease when one takes the GRE into account.

Study on Acupuncture for Side Effects of Etomidate Anesthesia

Objective: To evaluate the effect of acupuncture therapy on the side effect of Etomidate anesthesia and to determine the best timing of acupuncture intervention during Etomidate anesthesia. Methods: Female patients with rectal cancer scheduled to receive radical resection were randomly divided into four groups: a control group(group Ⅰ), a preoperative acupuncture group(group Ⅱ), an intraoperative acupuncture group(group Ⅲ), and a postoperative acupuncture group(group Ⅳ), 25 subjects in each group. The levels of serum cortisol, blood glucose, and gastrin of patients were monitored at the following time-points: preoperative(T0, when having entered the operating room), intraoperative(T1, 30 min after skin cutting), the end of operation(T2, after suturing skin), and postoperative(T3, postoperative 24 h). The cases with massive hemorrhage, unsteady vital sign during operation or operation time longer than 5 h were eliminated, and 92 cases were enrolled into the results of the study. Results: The blood sugar in the four groups increased significantly at T2 and T3, compared to T0(P < 0.05); the blood sugar reached((.(((1.5() mmol(( at T2 in group Ⅲ, and the increase was statistically significant compared to those of the other groups(P<0.05). The levels of serum cortisol of all patients were in normal range. Compare to T0, the cortisol level decreased in group Ⅰ, Ⅲ, at each point, and the decreases Ⅳ were statistically significant(P<0.05). Compared to the other groups, the cortisol level was increased at T1 and T3 in group Ⅱ, and the change was statistically significant(P<0.05). Compared to T0, the gastrin level at T3 increased in group Ⅰ, Ⅲand Ⅳ, but decreased in group Ⅱ, and the changes had statistical significance(P<0.05). Compared to the other groups, the decrease of gastrin level in group Ⅱat T3 was statistically significant(P<0.05). Conclusion: Acupuncture before operation can keep blood sugar and serum cortisol steady during Etomidate anesthesia and reduce gastrin after Etomidate anesthesia, hence regulating the Etomidate-related stress responses effectively.

Effect of opening the Drake Passage on the oceanic general circulation:A box model study

The impacts of opening the Drake Passage(DP) on the oceanic general circulation are examined.When the DP is open,wind stress at mid-and high latitudes gives rise to a wind-driven gyre,which induces a meridional heat exchange between mid-and high latitudes in the Southern Ocean.After the opening of the DP,the Antarctic Circumpolar Current(ACC) forms and its associated strong temperature front blocks the heat transport from mid-latitudes to high latitudes.A simple box model is formulated,in which the effects of the wind stress(for the case of DP closed) and the thermal front(for the case of DP open) on the variability of Antarctic Bottom Water(AABW) and North Atlantic Deep Water(NADW) are explored.The sensitivity experiments demonstrate that:(1) When the DP is closed,the enhancement of the wind-driven gyre leads to the decline of AABW formation in the Southern Ocean and the increase of NADW formation in the North Atlantic.As a result,water in high latitudes of the Southern Ocean becomes warmer,so does the bottom water of global ocean.(2) When the DP is open,there is no formation of AABW until the intensity of thermal front along ACC exceeds a threshold value(it is 4.03℃ in our model).Before the formation of AABW,temperature in most of the oceans is higher than that after the formation of AABW,which usually leads to the cooling of high latitudes of the Southern Hemisphere and the bottom water in global ocean.When the strength of the thermal front is lower than the critical value,there is no AABW formation,and temperature in most of the oceans is slightly higher.These results demonstrate that during the opening of the DP,changes in wind stress and the formation of the thermal front in the Southern Ocean can substantially affect the formation of AABW and NADW,thus changing the state of meridional overturning circulation in the global ocean.

INVERSE SCATTERING PROBLEM FOR ONE-DIMENSIONAL SCHRDINGER OPERATORS RELATED TO THE GENERAL STARK EFFECT

This paper disccusses the inverse scattering problem for one-dimensional Schrodinger operatorsrelated to the general Stark effect. We provide a ganeral framework which can be applied both to theStark-effect operator and the ordinary Schrodinger operator.